Maglev

MAGNETIC LEVITATION TRAIN

MAGLEV

Advantages: ¤ The highest speed of all public land transport ¤ Sufficiently low energy consumption, high ecological

compatibility ¤ Noiseless

In the late 1940s, Professor Eric Laithwaite of Imperial College in London developed the first full-size working model of the linear induction motor.

 In 1979, a 908 m track was opened in Hamburg for the first International Transportation Exhibition (IVA 79).

In Japan, there are two independently developed maglev trains, the development of the latter started in 1969, and Miyazaki test track had regularly hit 517 km/h (321 mph) by 1979

HISTORY. DEVELOPMENT.

In current electromagnetic suspension (EMS) systems, the train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below.

The major advantage to suspended maglev systems is that they work at all speeds, unlike electrodynamic systems which only work at a minimum speed of about 30 km/h (19 mph). 

In electrodynamic suspension (EDS), both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields. 

The magnetic field in the train is produced by either superconducting magnets

TECHNOLOGY. ELECTROMAGNETIC

SUSPENSION & ELECTRODYNAMIC SUSPENSION

JR-Maglev EDS suspension is due to the magnetic fields induced either side of the vehicle by the passage of the vehicle's superconducting magnets.

EDS Maglev Propulsion via propulsion coils.

PROS AND CONS OF DIFFERENT TECHNOLOGIES

Each implementation of the magnetic levitation principle for train-type travel involves advantages and disadvantages:

Steel-Wheel

Electromagnetic

Suspension

Electrodynamic

Suspension

Technology Pros Cons

EMS (Electromagnetic suspension)

Magnetic fields inside and outside the vehicle are less than EDS; proven, commercially available technology that can attain very high speeds (500 km/h (310 mph)); no wheels or secondary propulsion system needed.

The separation between the vehicle and the guideway must be constantly monitored and corrected by computer systems to avoid collision due to the unstable nature of electromagnetic attraction; due to the system's inherent instability and the required constant corrections by outside systems, vibration issues may occur.

EDS (Electrodynamic suspension)

Onboard magnets and large margin between rail and train enable highest recorded train speeds (581 km/h (361 mph)) and heavy load capacity; has demonstrated (December 2005) successful operations using high-temperature superconductors in its onboard magnets, cooled with inexpensive liquid nitrogen.

Strong magnetic fields onboard the train would make the train inaccessible to passengers with pacemakers or magnetic data storage media such as hard drives and credit cards, necessitating the use of magnetic shielding; limitations on guideway inductivity limit the maximum speed of the vehicle; vehicle must be wheeled for travel at low speeds.

Inductrack System

(Permanent Magnet EDS)

Failsafe Suspension—no power required to activate magnets; Magnetic field is localized below the car; can generate enough force at low speeds (around 5 km/h (3.1 mph)) to levitate maglev train; in case of power failure cars slow down on their own safely; Halbach arrays of permanent magnets may prove more cost-effective than electromagnets.

Requires either wheels or track segments that move for when the vehicle is stopped. New technology that is still under development (as of 2008) and as yet has no commercial version or full scale system prototype.

Earnshaw's theorem shows that any combination of static magnets cannot be in a stable equilibrium. However, the various levitation systems achieve stable levitation by violating the assumptions of Earnshaw's theorem.

EMS systems rely on active electronic stabilization. If superconducting magnets are used on a train above a

track made out of a permanent magnet, then the train would be locked in to its lateral position on the track. It can move linearly along the track, but not off the track.

STABILITY

MLX01 Maglev train Superconducting magnet Bogie

Major comparative differences exist between the two technologies. First of all, maglevs are not trains and are more similar to wingless aircraft than wheel-less trains. Maglev transport is non-contact, electric powered and controlled flight. It does not rely on the wheels, bearings and axles common to mechanical friction-reliant rail systems.

Maintenance Requirements Of Electronic Versus Mechanical Systems

All-Weather Operations Backwards Compatibility Efficiency Weight Noise Design Comparisons Control Systems

COMPARISON WITH CONVENTIONAL TRAINS

The END!

Thank you for your attention!